The Rover SD1 Story - Why did this Ferrari-inspired Rover fail?

The Rover SD1 was so nearly a game changer. It was an amazing follow-up to the Triumph 2000 & Rover P6, but it caused so much damage to the Rover name. It was a "space age" shape that looked like it had come right off the set of Blakes 7. And this came out of old, stodgy, British Leyland - the company that had brought us the Morris Marina and Austin Allegro! So why was this amazing car do so badly?
Video link: https://youtu.be/N9L7mrUj3mE